Abstract
Turbulent flow characteristics of open channel flows in a rectangular trench are analyzed by the particle image velocimetry (PIV) and the large eddy simulation (LES). The effects of the depth of the trench and the Froude number are discussed in detail. The results for the lower Froude number show a favorable agreement between PIV and LES except near the free surface. It is suggested that the separated shear layer has an organized structure composed of longitudinal vortices. The effect of Froude number is clearly indicated by using the convection diagrams showing the space-time variations of the velocity field.
